Printers include, without limitation, computer printers, copiers, and facsimile machines. Some printers, such as inkjet printers, print by printing closely-spaced ink dots on a print medium such as paper. Conventional inkjet printers include those having a carrier with two (or more) printheads such as a color printhead and a mono or a photo printhead. Typically, a color printhead prints cyan, magenta and yellow dots, a mono printhead prints black dots, and a photo printhead prints black, cyan and magenta dots. Typically, to print a print swath requiring use of the two printheads, the carrier moves across the paper in a first print pass (or multiple print passes without advancing the paper) with the first printhead under the command of a printhead driver. Then, without advancing the paper, the carrier again moves across the paper in a second print pass (or multiple print passes without advancing the paper) while printing with the second printhead under the command of the same printhead driver. Conventionally, faster printing using two printheads during the same print pass of the carrier across the paper required two printhead drivers and double the memory which significantly added to the cost of the printer.
What is needed is an improved method, an improved printer, and/or an improved printhead driver for printing using two printheads.